Absence of metallicity in K-doped picene: importance of electronic correlations.
Absence of metallicity in K-doped picene: importance of electronic correlations.
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DOI：
10.1103/physrevlett.110.216403
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发表时间：
2012-10
影响因子：
8.6
通讯作者：
A. Ruff;M. Sing;R. Claessen;Hunpyo Lee;M. Tomić;H. Jeschke;R. Valentí
中科院分区：
文献类型：
--
作者：
A. Ruff;M. Sing;R. Claessen;Hunpyo Lee;M. Tomić;H. Jeschke;R. Valentí
钾掺杂的picene（K（x）picene）在x=3时是一种超导体，其临界温度可达18K。本文采用光电子能谱和从头算密度泛函理论结合动力学平均场理论（DFT+DMFT）研究了K掺杂的六亚甲基二苯薄膜的电子结构。实验上我们观察到，除了由于在低K浓度（x = 1）下缺乏均匀化学势而导致的假谱权重外，谱总是显示有限的能隙。这一结果得到了我们的DFT+DMFT计算的支持，该计算提供了明确的证据，证明K（x）picene在整数掺杂浓度x=1、2和3时是Mott绝缘体。我们讨论了各种方案，以了解与以前的超导性和金属行为的报告的差异。
Potassium-doped picene (K(x)picene) has recently been reported to be a superconductor at x=3 with critical temperatures up to 18 K. Here we study the electronic structure of K-doped picene films by photoelectron spectroscopy and ab initio density functional theory combined with dynamical mean-field theory (DFT+DMFT). Experimentally we observe that, except for spurious spectral weight due to the lack of a homogeneous chemical potential at low K concentrations (x≈1), the spectra always display a finite energy gap. This result is supported by our DFT+DMFT calculations which provide clear evidence that K(x)picene is a Mott insulator for integer doping concentrations x=1, 2, and 3. We discuss various scenarios to understand the discrepancies with previous reports of superconductivity and metallic behavior.